This invention relates generally to vehicles and more particularly to vehicles having both a primary motor and an auxiliary motor.
As is well known, conventional vehicles such as passenger cars sometimes become stalled in mud or snow or on ice when the drive wheels, usually the rear wheels, lose traction. With the increasing popularity of compact passenger vehicles, traction problems under such adverse conditions have become more common. Compact and subcompact vehicles are specially designed to be light in weight and traction problems are therefore inherent. Furthermore, compacts and subcompacts generally have small tires and wheels which, as is well known, have relatively high rolling resistance. The increased use of plastics and other lightweight materials in these and other vehicles has made such traction problems even more widespread.
Traditional passenger cars having two-wheel drive are especially susceptible to stalling under adverse road conditions. It has long been known that full-time four-wheel-drive vehicles, such as military or recreational vehicles, are especially adapted for travel under adverse road conditions. Such full-time four-wheel-drive vehicles are provide with front and rear drive axles operatively and drivingly connected to a single mover such as a gasoline engine. Vehicles have also been designed with part-time four-wheel-drive capabilities. In these vehicles wheel locks or clutches are manually or automatically selectively engageable to transform the vehicle from a two-wheel-drive to a four-wheel-drive system. Although full or part-time four wheel-drive vehicles have proved highly successful in specific situations, the large drive mechanisms used in these vehicles are generally unsuitable in size and weight for the presently popular compact and subcompact vehicles.